Mobile communication system, resource switching method thereof, network control apparatus included therein, same and network control method

ABSTRACT

The present invention relates to a mobile communication system comprising a structure for realizing “network seamless” for roaming between different kinds of networks, “contents seamless” for converting different kinds of encoding or media therebetween, and “device seamless” for making it possible to utilize optimum I/O devices in conformity to surrounding environments. This mobile communication system detects a change in an environment in use concerning an object such as a mobile terminal, for example, notifies at least one apparatus relating to the change of the result of detection, sets various resources constituting a network in conformity to a new environment, and switches them. This makes it possible to construct a seamless network which automatically eliminates seams (restrictions) concerning changes in the environment and the like.

TECHNICAL FIELD

[0001] The present invention relates to a mobile communication system, aresource switching method thereof, and a network control apparatus andnetwork control method included in the same.

BACKGROUND ART

[0002] Conventional mobile communication systems have been realized asinformation providing systems in which users operate mobile terminals(mobile stations) so as to connect them to the Internet and browse, viathe mobile terminals, web information provided by WWW servers. Examplesof such information providing systems include i-scheme service (servicename) provided by NTT DoCoMo, Inc., and the like.

DISCLOSURE OF THE INVENTION

[0003] The inventors studied the conventional mobile communicationsystems and, as a result, have found the following problems. Namely,while browsing information via a mobile terminal concerning aninformation providing service in the conventional mobile communicationsystems, a user cannot interchange visual information and audioinformation with each other without manually switching contents evenwhen images shown on a display become invisible due to the surroundingdarkness, the user rides on a train or bus, and so forth, for example.In other words, there have been no mobile communication systems whichcan browse web information items provided by WWW servers while switchingthem in response to environments in which mobile terminals are used.

[0004] Also, there have been no mobile communication systems enablingcontents to be automatically switched, for example, when a user browsinginformation via a mobile terminal changes the terminal for browsinginformation. Further, there have been no mobile communication systemswhich can browse network resources while switching them according tocontents to be browsed, for example, in the case where provided contentsare changed from visual information to audio information, unless a userbrowsing information via a mobile terminal manually switches the networkresources.

[0005] For overcoming the above-mentioned problems, it is an object ofthe present invention to provide a mobile communication systemcomprising a structure for automatically eliminating various seams(restrictions) in mobile communications and making it possible toconstruct a seamless network which can respond to environmental changesand the like, a resource switching method therefor, a network controlapparatus included in the same and a network control method.

[0006] For achieving the above-mentioned object, the mobilecommunication system according to the present invention comprises, atleast, detecting means, reporting means, setting means, and switchingmeans. The detecting means detects at least a change in an environmentin which an object to be inspected exists and a change in a capabilityof the object to be inspected. The reporting means notifies at one ormore apparatuses relating to the change detected by the detecting meansof at least a result of the detection. The setting means newly sets atleast one of a network resource and an information format in conformityto the change detected by the detecting means. Then, the switching meansswitches the network resources and information format into a content setby the setting means.

[0007] In the mobile communication system comprising the configurationmentioned above, the object to be inspected includes at least one of acommunication terminal, transmission means for a radio area, andtransmission means within a network. The network resource includes atleast one of a wireless communication channel, a transmitter/receiver, aline within a network, a communication node apparatus, a communicationterminal, an information switching apparatus, and an informationconverting apparatus.

[0008] In the mobile communication system according to the presentinvention, the switching means includes information converting apparatuswhich carries out, as the switching of information format, changing ofmedia (sound, image, text, etc.) transferred over a network or changingof a transmission quality in the same media such as encoding scheme andencoding rate. Here, the information converting apparatus includes, atleast, a network interface surface, an information converting section,and a control section. The network interface section transmits/receivesinformation to/from a resource constituting a network. The informationconverting section converts the format of information captured by way ofthe network interface section into another format, and transmits thusconverted information onto the network by way of the network interfacesection. The control section controls the information converting sectionaccording to an instruction from a network control section controllingthe network.

[0009] The network control method according to the present inventionsuccessively executes a receiving step, a determining step, and acontrolling step. Here, the receiving step receives a detection reportof at least one of a change in an environment in which an object to beinspected exists and a change in a capability of the object to beinspected from the object to be inspected. The determining stepdetermines at least one of a network resource and an information formatsuitable for the change specified by the detection report received fromthe object to be inspected. The controlling step controls the object tobe inspected concerning at least one of the determined network resourceand information format so that the object conforms to the detectedchange. The network control apparatus realizing such a network controlmethod comprises receiving means, determining means, and control meansfor executing the receiving step, determining step, and controlling steprespectively.

[0010] The resource switching method of the mobile communication systemcomprising the structure mentioned above comprises a detecting step, areporting step, a setting step, and a switching step. The detecting stepdetects at least one of a change in an environment in which an object tobe inspected exists and a change in a capability of the object to beinspected. The reporting step notifies at least one of apparatusrelating to the change detected by the detecting means of a result ofthe detection. The setting step newly sets at least one of a networkresource and an information format in conformity to the change detectedby the detecting step. Then, the switching step switches the networkresource and information format into a content newly set by the settingstep. Specifically, the switching step includes, as the switching ofinformation format, a step of changing media (sound, image, text, etc.)transferred over a network or changing a transmission quality in thesame media such as encoding scheme and encoding rate.

[0011] In the mobile communication system according to the presentinvention and the resource switching method thereof, as mentioned above,when a change in an environment in use or the like concerning an objectis detected in any of apparatus in the mobile communication system,e.g., a mobile terminal, an information processing apparatus connectedthereto, a node within a network, and a node connected to the network,the change in environment or the like is reported to at least oneapparatus relating to the change, and various resources are set up inthus notified apparatus so as to respond to the new environment or thelike and switched. Thus, the mobile communication system and theresource switching method thereof automatically eliminate various seams(restrictions) in mobile communications, thereby making it possible toconstruct a seamless network which can respond to various environmentalchanges. Namely, the mobile communication system and the resourceswitching method thereof enable “network seamless” for roaming betweendifferent kinds of networks, “contents seamless” for convertingdifferent kinds of encoding or media therebetween, and “device seamless”for making it possible to utilize optimum I/O devices in conformity tosurrounding environments. Also, such a configuration efficiently detectschanges in electromagnetic wave environments in wireless areas, changesin environments surrounding terminals, changes in capabilities ofterminals, changes in transmission networks, changes in providedcontents, and the like.

[0012] Here, “transmission means for a radio area” refers to a wirelesscommunication channel for transmitting information, apparatus fortransmitting/receiving information in this channel, and the like.Setting parameters of the wireless communication channel vary dependingon wireless access schemes. In FDMA scheme, for example, the wirelesschannel is represented by a radio frequency. It is represented by aradio frequency and a slot number in TDMA scheme, and by a radiofrequency and a spreading code in CDMA scheme. On the other hand,“transmission means within a network” is a line connecting communicationnodes, and includes various schemes such as STM, ATM, and WDM. Acommunication node apparatus for carrying out communications by a line,and the like are included in the “transmission means within a network.”Further, “network resource” refers to transmission means fortransmitting information, for example, such as wireless communicationchannels, transmitters/receivers, lines within a network, communicationnode apparatus, communication terminals, and the like. Informationswitching apparatus, information converting apparatus, and the like arealso included in the “network resource.”

[0013] Embodiments according to the present invention will become morefully understood from the detailed description given hereinbelow. Theseembodiments are given by way of illustration only, and thus should notbe considered limitative of the present invention.

[0014] Also, further scope of applicability of the present inventionwill become apparatus from the detailed description given hereinafter.However, it is clear that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, and various changes and modificationswithin the spirit and scope of the invention will become apparent tothose skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a diagram showing an example of schematic configurationof the mobile communication system according to the present invention;

[0016]FIG. 2 is a block diagram showing a schematic configuration of theNW control section 102 shown in FIG. 1;

[0017]FIG. 3 is a block diagram showing a schematic configuration of thecommunication terminal shown in FIG. 1;

[0018]FIG. 4 is a block diagram showing a schematic configuration of theinformation terminal shown in FIG. 1;

[0019]FIG. 5 is a block diagram showing a schematic configuration of theinformation converting apparatus shown in FIG. 1;

[0020]FIG. 6 is a table for explaining an example of informationconversion carried out in the information converting apparatus shown inFIG. 5;

[0021]FIG. 7 is a chart showing an example of communication sequence ina case (media conversion) where, in response to a change in anenvironment surrounding a terminal, contents transmitted to the terminalare changed from text information to audio information in the mobilecommunication system according to the present invention and the resourceswitching method thereof;

[0022]FIG. 8 is a chart showing an example of communication sequence ina case where the rate of an image codec is changed in response to achange in a wireless environment (transmission capability) in the mobilecommunication system according to the present invention and the resourceswitching method thereof;

[0023]FIG. 9 is a chart showing an example of communication sequence ina case where media and transmission means for contents are changed inresponse to a change in an environment surrounding a terminal in themobile communication system according to the present invention and theresource switching method thereof; and

[0024]FIG. 10 is a view showing an example of image realizing a videoconference employing the mobile communication system according to thepresent invention.

BEST SCHEMES FOR CARRYING OUT THE INVENTION

[0025] In the following, embodiments of the mobile communication systemaccording to the present invention and the resource switching methodthereof will be explained with reference to FIGS. 1 to 10. In theexplanation of the drawings, parts and constituents identical to eachother will be referred to with numerals or letters identical to eachother without repeating their overlapping descriptions.

[0026]FIG. 1 is a diagram showing an example of schematic configurationof the mobile communication system according to the present invention.This mobile communication system comprises, at least, a network NW100,information communication terminals, an information converting apparatus400 connected to the network NW100, and a contents server group 500. Theinformation communication terminals include a separate type informationcommunication terminal 250 a constituted by a communication terminal 200and an information terminal 300 connected thereto, and an integratedinformation communication terminal 250 b in which they are integratedtogether.

[0027] The network NW100 includes an NW control section 102, a wirelessinterface section 104, a service server interface section 106, and agateway section 108; connects the communication terminal 200,information converting apparatus 400, and contents server group 500 toeach other; and switches lines and packets for mobile communications.The network NW100 may include one of networks such as the Internet,intranet, LAN (either wired or wireless), public telephone network,(either analog or digital), mobile line switching network/mobile packetswitching network of PDC/PDC-P scheme or the like, paging network, PHSnetwork, and satellite communication network. Also, the network NW100includes a network connected to a plurality of routers through whichpackets are transmitted while being routed.

[0028] The NW control section 102 is connected to the wireless interfacesection 104, service server interface section 106, and gateway section108; comprises a storage for storing network control programs, programsspecifying various communication processing procedures, and requireddata; and controls the network NW100. The wireless interface section 104is connected to the NW control section 102 and enables wirelesscommunications with the communication terminal 200. The service serverinterface section 106 is connected to the NW control section 102, andhas an interface function with the information converting apparatus 400and contents server group 500. The gateway section 108 is connected tothe NW control section 102, and has a gateway function with respect toother networks.

[0029]FIG. 2 is a block diagram showing a schematic configuration of theNW control section 102 shown in FIG. 1. The NW control section 102 isdepicted in FIG. 1 as being concentrated at one location within thenetwork 100. However, the NW control may also be carried out at aplurality of locations in a decentralized manner (i.e., a plurality ofNW control sections may be provided within the network NW 100). When thenetwork NW100 is formed by a plurality of routers and transmnissionlines and the like connecting them, for example, the NW control sectionmay be constituted by the plurality of routers.

[0030] The configuration and operation of the NW control section 102will now be explained.

[0031] The NW control section 102 comprises, at least, a control section110, a resource managing section 112, a line switching section 114, acontents managing section 116, and an information conversion managingsection 118. The control section 110 controls the whole NW controlsection 102 in a centralized manner. Also, the control section 110controls mutual information exchanges between a plurality of functionblocks connected thereto. Further, as required, the control section 110instructs the resource managing section 112 to change amounts ofallocation of various resources assigned to or used in terminals, calls,flows, or sessions under control or stop allocating them. In addition,when communications are newly started, the control section 110 instructsthe resource managing section 112 to allocate resources. On the otherhand, concerning terminals, calls, flows, or sessions under control, thecontrol section 110 instructs the line switching section 114 to switchlines for transmitting information within the network NW100 or carry outline switching/routing control for switching packet routing in the caseof a packet network as required. Also, the control section 110 ordersrouting control of information signals from other networks as required.The control section 110 instructs the contents managing section 116 onmedia, encoding schemes, encoding rates, and the like of informationbeing communicated or about to be communicated for each terminal, call,flow, or session. When information exchange is necessary in terminals,calls, flows, or sessions under control, the control section 110instructs the information conversion managing section 118 on informationmedia, encoding schemes, encoding rates, and the like before and afterconversion.

[0032] The resource managing section 112 is connected to the controlsection 110, and orders changes in allocation of various resources(resource management) such as the wireless interface section 104,wired/wireless information transmission lines within the network NW100such as wired transmission lines within the network which are notdepicted, and apparatus for transmission, and amounts of allocation ofresources for each terminal, call, flow, or session. The line switchingsection 114 is connected to the control section 110 and controlsoperations of the gateway section 108. The line switching section 114not only controls routing of information signals from other networks,but also switches lines for transmitting information within the networkNW100 and carries out switching control (line switching/routing control)of packet routing for each terminal, call, flow, or session in a packetnetwork.

[0033] On the other hand, the contents managing section 116 is connectedto the control section 110. For each terminal, call, flow, or session,the contents managing section 116 manages provided contents, informationmedia, encoding schemes, encoding rates, and the like, and orders media,encoding schemes, encoding rates, and the like of information beingcommunicated or exchanges information with the service server group 500and information converting apparatus 400 by way of the service serverinterface section 106 as required.

[0034] The information conversion managing section 118 is connected tothe control section 110. The information conversion managing section 118determines whether or not information conversion is required for aterminal, call, flow, or session, and manages information media,encoding schemes, encoding rates, and the like before and afterconversion when it is determined that the information conversion isnecessary. Also, when necessary, the information conversion managingsection 118 instructs, by way of the service server interface section106, the service server group 500 and information converting apparatus400 on media, encoding schemes, encoding rates, and the like ofinformation being communicated or exchanges information therewith.

[0035] The communication terminal 200 shown in FIG. 1 is connected tothe information terminal 300, and carries out wireless communicationswith the wireless interface section 104. Here, the communicationterminal 200 may be any of a pager, a PHS terminal a mobile terminal(including one conforming to IMT-2000), a mobile information terminal(PDA) equipped with a communication function, and the like. Inparticular, the mobile terminal may be one having an email function or afunction of getting access to the Internet (e.g., an i-scheme (servicename) terminal provided by NTT DoCoMo, Inc. (company name), and thelike).

[0036]FIG. 3 is a block diagram showing a schematic configuration of thecommunication terminal 200 shown in FIG. 1. The communication terminal200 comprises, at least, a control section 202, an antenna section 204,a network detecting section 206, network communicating sections 208, anda terminal interface section 210. The control section 202 controls thewhole communication terminal 200 in a centralized manner. The antennasection 204 is connected to the network detecting section 206 andnetwork communicating sections 208, and enables wireless communicationswith the wireless interface section 104. The network detecting section206 is connected to the control section 202 and antenna section 204, anddetects at least one network NW100 to which the communication terminal200 is connected. The network communicating sections 208 are connectedto the control section 202 and antenna section 204, and carries outcommunications with at least one network NW100 detected by the networkdetecting section 206. The terminal interface section 210 is connectedto the control section 202, and has an interface function with theinformation terminal 300.

[0037] The information terminal 300 shown in FIG. 1 is connected to thecommunication terminal 200, and browses contents from the contentsserver group 500 by way of the network NW100. Also, the informationterminal 300 comprises a structure for detecting an environment (statusof placement) in which it exists. For example, the information terminal300 can be realized if peripherals such as various sensors, printers,displays, and image scanners are connected to an information processingapparatus including known personal computers, workstations, andinformation processing terminals such as PDA while software (includingprograms, data, and the like) for realizing information providingservices of the mobile communication system according to the presentinvention is installed in the information processing apparatus.

[0038]FIG. 4 is a block diagram showing a schematic configuration of theinformation terminal 300 shown in FIG. 1. The information terminal 300comprises, at least, a control section 302, operation I/O sections 304,an audio I/O section 306, a visual I/O section 308, an environmentdetecting section 310, a communication interface 312, local devices 314,and a storage section 316. The control section 302 controls the wholeinformation terminal 300 in a centralized manner. The control section302 has an internal memory for storing control programs such as an OS(Operating system), programs defining various processing procedures andthe like, and required data; and carries out various informationprocessing operations according to these programs and the like. Theoperation I/O sections 304 are connected to the control section 302, andmakes it possible to input/output operations. The operation I/O sections304 include, for example, various pointing devices such as a mouse,keyboards, image scanners, and digitizers operated by users. The audioI/O section 306 is connected to the control section 302 and includes,for example, microphones, speakers, and the like which make it possibleto input/output sounds. The visual I/O section 308 is connected to thecontrol section 302 and includes, for example, video cameras, digitalcameras, and display apparatus such as displays which make it possibleto input/output images. The environment detecting section 310 isconnected to the control section 302 and includes apparatus fordetecting an environment in which the information terminal 300 isplaced, for example, such as apparatus for detecting an electromagnaticwave environment, apparatus for detecting surrounding environmentinformation (e.g., inside a train or bus, inside a theater, hospital, orthe like, etc.) reported from the outside by local wireless means suchas Bluetooth, apparatus for detecting the outside brightness, andtemperature detecting apparatus. The detecting means for detectingchanges in an environment in which the object to be inspected exists mayalso be provided in other apparatus such as the communication terminal200. The communication terminal 312 is connected to the control section302, and has an interface function with the terminal interface section210 of the communication terminal 200. The local devices 314 areconnected to the control section 302, and realize respective functions.The storage section 316 is storage means such as memory devices like RAMand ROM, fixed disk devices such as hard disks, flexible disks, andoptical disks; and stores various tables, files, databases, and the likefor use in various processing operations.

[0039] The information communication terminal 250 b shown in FIG. 1 isan integrated information communication terminal equipped with thefunction of the communication terminal 200 and the function ofinformation terminal 300, and comprises constituents similar to those ofthe communication terminal 200 and information terminal 300.

[0040] In the embodiment comprising the foregoing configuration, theinformation terminal 300 carries out wireless communications with thenetwork NW100 by way of the communication terminal 200, so as to receivedata concerning contents provided by the contents server group 500,thereby making it possible to browse the contents by utilizing a browserincorporated therein. As will be shown in detail in the following, if achange in an environment or the like concerning an object is detectedhere in any apparatus of the mobile communication system, at least oneapparatus relating to the change in environment or the like is notifiedof the result of detection. In thus notified apparatus, variousresources are set up so as to respond to the changed environment, andthey are automatically switched.

[0041]FIG. 5 is a block diagram showing the configuration of theinformation converting apparatus 400 shown in FIG. 1.

[0042] The information converting apparatus 400 has a function ofconverting contents from the contents server group 500 or informationfrom a communication terminal existing in the network NW100 or in othernetworks into another information format according to an instructionfrom the NW control section 102. As shown in FIG. 5, the informationconverting apparatus 400 comprises an NW interface section 402, aninformation converting section 404, and a control section 406. The NWinterface section 402 is connected to the service server I/F section 106in the network NW100, and transmits/receives signals to/from the NWcontrol section 102 and contents server group 500. The informationconverting section 404 is connected to the NW interface section 402 andcontrol section 406, and converts information signals of the contentsfed from the NW interface section 402 into another information formataccording to an instruction from the control section 406. The controlsection 406 receives an instruction concerning the informationconversion from the NW control section 102 by way of the NW interfacesection 402, and notifies the information converting section 404 of thusinstructed information.

[0043] The information converting section 404 has at least one functionnecessary for the system selected from a function (first function) ofchanging a transmission quality such as encoding scheme and encodingrate in the same media and a function (second function) of changing themedia itself. An example of the first function corresponds to a casewhere the encoding rate of 12.2 kbit/s is converted to that of 8 kbit/sin audio media. Also, even in the case of encoding the same sound, thereare various audio encoding schemes depending on differences in encodingrates and sound qualities. The above-mentioned first function alsoincludes functions of converting information between the audio encodingschemes. An example of the second function corresponds to a case wheretext information is converted into audio information. Namely, it is afunction of reading out text information by use of a speech synthesizingtechnique or the like. The second function also includes a case whereaudio information is converted into text information by use of a speechrecognition technique or the like. Further, various informationconversions such as conversion of visual information into audioinformation explaining the image thereof can be considered. FIG. 6 is atable showing a plurality of examples concerning the informationconversions mentioned above.

[0044] The information converting apparatus 400 comprising the structurementioned above operates if it is determined that an informationconversion is necessary when carrying out communications in the NWcontrol section 102. Namely, in the NW control section 102, whether aninformation conversion is necessary or not is determined according to anenvironment or resource status in a call, flow, or session for carryingout communications or in communications being carried out. If it isdetermined that the information conversion is necessary in the NWcontrol section 102, information indicating this fact will be reportedto the information converting apparatus 400 by way of the service serverI/F section 106. Therefore, such an indication of information conversionis carried out for each call, flow, or session.

[0045] In the information converting apparatus 400, thus reportedinformation indicative of the information conversion is fed into thecontrol section 406 by way of the NW interface section 402. According tothus indicated contents, the control section 406 instructs theinformation converting section 404 on the information conversionmatching the indicated contents.

[0046] An example of the instruction from the control section 406 to theinformation converting section 404 is an indication of informationconversion such as one shown in FIG. 6. The ID numbers in FIG. 6 arethose for identifying terminals, calls, flows, or sessions. For example,the first example (ID No. 1) shown in FIG. 6 is an informationconversion corresponding to the above-mentioned first function. In thiscase, the control section 406 instructs the information convertingsection 404 to convert audio information at 12.2 kbit/s into that at 8kbit/s. Upon this instruction, a sound at 12.2 kbit/s inputted by way ofthe NW interface section 402 is converted into that at 8 kbit/s in theinformation converting section 402 and then is outputted to the NWinterface section 402 again. Thus converted sound (audio information) at8 kbit/s is transmitted by way of the service server I/F section 106 tothe aimed terminal of the call, flow, or session corresponding to IDNo. 1. The second and third examples (ID Nos. 2 and 3) shown in FIG. 6are information conversions between text and sound corresponding to thesecond function, whereas the fourth example shown in FIG. 6 is aninformation conversion between moving and still images corresponding tothe second function.

Object to Detect Change

[0047] The object to be inspected may be a change in an electromagneticwave environment in transmission means for a radio area. The change inelectromagnatic wave environment corresponds to a change (decrease) in atransmission quality in a case where a communicating terminal is movingindoors from the outdoors, or an amelioration of a transmission qualityattained when the site of communication is moved from a location such asa shade of a building where the electromagnatic wave is in a weak stateto a location such as the outside of shade where the state ofelectromagnatic wave is improved, for example. Also, when a terminal ismoved, the electromagnatic wave of the cell currently in communicationmay become so weak that electromagnatic waves in its neighboring cellbecome stronger. As a method of determining them, changes in theelectromagnatic wave environment may be detected in the communicationterminal 200 according to cell determination (e.g., comparison ofreception levels of “perch channel” in surrounding cells) ortransmission quality monitoring (e.g., measurement of SIR, the bit errorrate of a pilot signal, transmission delay, and the like).

[0048] A case carrying out the cell determination will now be explained.In cellular type mobile communications, an area is covered with aplurality of cells. Base stations in the cells transmit signals at thesame transmission power with respective frequencies (perch channels)different from each other. In the communication terminal 200, since thefrequencies of perch channels have been known beforehand, the NWdetecting section 206 can detect that the optimal base station forcommunications has changed by measuring the respective reception levelsof perch channels of a plurality of base stations and comparing theresults of measurement to each other.

[0049] In the detection of changes in a transmission quality, on theother hand, the communication terminal 200 measures various transmissionquality indices in the NW communicating sections 208 duringcommunications. For example, SIR, which is the ratio in power betweensignal and interference, is uniquely related to the bit error rate andframe non-reception rate, which are transmission qualities ofinformation, so that the bit error rate and frame non-reception ratebecome lower as the SIR is higher. According to the SIR measured byutilizing it, changes in an electromagnetic wave environment aredetected. Also, measurement of the bit error rate in a pilot signalmakes it possible to measure transmission loss. The pilot signal is asignal whose contents have been known beforehand on the receiving side,so that a transmission quality can be measured when how much this signalis erroneously transmitted is verified, whereby changes in theelectromagnatic wave environment are detected. Also, transmission delaytime is one of transmission qualities. The transmission delay time isobtained when the time required for sending a measurement packet formeasuring transmission delay from the communication terminal 200 to abase station and then sending back this measurement packet from the basestation to the communication terminal 200 is measured. This can also beutilized for detection since, when the electromagnatic wave environmentchanges, the number of resending operations for transmission may change,for example, thereby affecting the transmission delay.

[0050] Also, the object to be inspected may be changes in surroundingenvironments provided by the surroundings of a terminal, such as a rideon a bus or train. Therefore, changes in surrounding environmentsdetected by information provided by local wireless means such aswireless LANs, infrared communications, and Bluetooth can become theobject to be inspected. The NW detecting section 206 in thecommunication terminal 200, and the environment detecting section 310 inthe information terminal 300 are provided with local wirelessinterfaces. Local wireless systems have been introduced into buses,trains, buildings of libraries and the like, and so forth, in which thecommunication terminal 200 and information terminal 300 can receivesignals by way of their interfaces, whereas changes in surroundingenvironments can easily be detected if the system is constructed so asto notify that it is inside a moving body such as a bus or train, forexample, or inside a building, while the terminals can obtain thisnotification from signals received by the interfaces.

[0051] The object to be inspected may be changes in capabilities of aterminal such as a change from a terminal capable of displayinghigh-density images to one incapable thereof. In this case,modifications in the configuration accompanying changes in terminalcapabilities can also be detected automatically in the NW controlsection 102 of the network NW100, the communication terminal 200, andthe like.

[0052] Modifications in networks in use, such as those in a case where acommunication path is changed to a network having a differenttransmission quality, terminal capability, or the like, may become theobject to be inspected. An example of this case is one where acommunication terminal which can utilize both of a cellular mobilecommunication system and a wireless LAN system is switched between thesedifferent networks. In the case where the communication terminal 200 isinitially communicating in the cellular mobile communication system,whether the wireless LAN system, which is the other system, can beutilized or not is determined by measuring the reception level or thelike in the NW detecting section 206. In the case where the wireless LANsystem is more favorable for the user from the viewpoints oftransmission quality, capability, and the like while communications arepossible, switching (changing) is carried out between the systems(networks).

[0053] Also, changes in provided contents, such as those in the casewhere contents including moving images and sounds are switched tocontents including still images and texts, can become the object to beinspected. In this case, changes in the provided contents can bedetected if the contents provided by the contents server group 500 aremanaged in a centralized manner by the contents managing section 116 ofthe network NW100 and the like.

Notification of Change

[0054] When an environmental change or capability change is detectedconcerning the above-mentioned object to be inspected, its relatedapparatus or function is notified of the result of detection. Namely,information needed after the change or information concerning the mediato be used, a required quality, and the like are reported to necessaryapparatus and the like, whereby a network resource required fortransmission is secured. For example, a change in the environment wherethe object to be inspected exists or in the capability thereof isreported from the terminal or the like to the network NW100, or viceversa.

Setup of New Environment

[0055] Each apparatus or function thus notified of the change secures aresource and the like, and sets up a communication environment (awireless channel, transmission means within a network, or the like). Forexample, when the network NW100 is notified, under the control of thecontrol section 110 in the NW control section 102, the resource managingsection 112 reallocates resources, the line switching section 114allocates network lines satisfying required transmission quality, thecontents managing section 116 investigates media of provided contentsand the like, and the information converting section 118 prepares forconverting media and so forth.

Switch to New Environment

[0056] Each apparatus or function having completed the setup asmentioned above switches to a new communication environment or the like.

[0057] Therefore, while communication environments and the like have notconventionally been switchable in response to user environments, themobile communication system according to the present invention and theresource switching method thereof can automatically execute switching inresponse to environments. For example, switching in the same media ispossible in such a manner that, in order to attain stronger resistanceto errors in the state where the transmission quality is unfavorable,the audio codec is changed to one with a decreased amount of audioinformation and increased information bits for correcting errors, thesound quality is changed in conformity to surrounding environments, thesize and fineness of letters are changed so as to be easily seen byusers, and so forth. In addition, switching between different media ispossible, for example, such that visual information is automaticallyswitched to audio information when the surroundings become dark.

[0058] Further, if the setup is effected such that contents andcommunication means are converted and switched automatically in responseto changes in the capability of a terminal, or so as to secure andmodify resources such that each function of the network, wirelesstransmission, and terminal responds to a change from contents consistingof text information alone to contents including visual information, theapparatus, functions, and the like can be switched in a form conformingto a condition required for contents.

[0059] Here, one skilled in the art can readily see that the mobilecommunication system and the resource switching method thereof areapplicable to bidirectional communications such as videophone systems.

[0060] An example of operations of thus configured mobile communicationsystem according to the present invention and the resource switchingmethod thereof will now be explained with reference to FIGS. 7 to 10.

[0061] (1) Case where a change in an environment surrounding a terminalis detected, and a media conversion for contents is carried out.

[0062]FIG. 7 is a chart showing an example of communication sequence inthe case where contents transmitted to a terminal are changed from textinformation to audio information when an optical sensor detects that thesurroundings of the terminal have become dark. Here, FIG. 7 conceptuallyshows only the part relating to the present invention in thecommunication sequence.

[0063] First, the information terminal 300 receives contents of textinformation from the contents server group 500 by way of the networkNW100 (step S702).

[0064] The environment detecting section 310 of the information terminal300 detects an environmental change when the surrounding brightness islower than a predetermined threshold (step S704). When notified of theenvironmental change, the control section 302 refers to setupinformation stored in the storage section 316 for responding to thechange. Then, the control section 302 prepares for allocating variousresources so as to change the contents from text information to audioinformation according to the referred setup information.

[0065] Subsequently, the control section 302 transmits an audioinformation switching request to the communication terminal 200 by wayof the communication interface 312, whereas the audio informationswitching request is sent to the control section 110 of the networkNW100 by way of the communication terminal 200 (step S706).

[0066] The control section 110 of the NW control section 102 notifiesthe contents managing section 116 and information conversion managingsection 118 to change text information to audio information (mediaconversion instruction), and also instructs the correspondinginformation converting apparatus 400 and contents server group 500 to doso by way of the service server interface section 106 (step S708). As aconsequence, the text information provided by the contents server group500 is fed into the information converting apparatus 400, and this textinformation is converted into audio information in the informationconverting apparatus 400 (step S710). The conversion from textinformation to audio information in the information converting apparatus400 can be effected by utilizing a text/sound converting apparatus shownin Japanese Patent Application Laid-Open No. HEI 5-165486, and the like,for example.

[0067] The control section 110 of the NW control section 102 notifiesthe resource managing section 112 to change a resource within thenetwork NW to a resource corresponding to an audio signal, e.g., anetwork resource of a line switching scheme, whereby the resourcemanaging section 112 allocates resources in the network NW including aconnection from the information converting apparatus 400 to the terminal(step S712). On the other hand, the control section 110 of the NWcontrol section 102 notifies the resource managing section 112 to changea wireless resource to a resource corresponding to the audio signal,whereby the resource managing section 112 sets and allocates wirelessresources (step S714 to step S716).

[0068] After the resources are completely allocated, a resource settingcompletion report is transmitted from the communication terminal 200 tothe information terminal 300 (step S718). In the information terminal300, switching of resources is executed (step S720), and contents ofaudio information are received (step S722). Also, the informationterminal 300 notifies the communication terminal 200 and the NW controlsection 102 of the network NW100 of the switching completion report(step S724).

[0069] Due to the foregoing operation, not only various old resourcesare released in the communication terminal 200, network NW100,information converting apparatus 400, and contents server 500 (stepS726), but also the old network resources in wireless channel and inlines within the network NW100 (lines within the NW) are released (stepS728).

[0070] Though the above-mentioned embodiment exemplifies a case wherethe communication terminal 200 and information terminal 300 are realizedas housings independent from each other, i.e., as the separate typeinformation communication terminal 250 a (see FIG. 1), the informationcommunication terminal is not restricted to such a form, whereas onehousing in which the communication terminal and information terminal areappropriately assembled together, i.e., the integrated informationcommunication terminal 250 b (see FIG. 1), may be employed as well.

[0071] (2) Case where a change in a wireless environment (transmissioncapability) is changed, and the rate of image codec is converted.

[0072]FIG. 8 is a chart showing an example of communication sequence inthe case where a change in a wireless environment (transmissioncapability) is detected, and the rate of image codec is converted. Here,FIG. 8 conceptually shows only the part relating to the presentinvention in the communication sequence.

[0073] First, the information terminal 300 receives high-rate visualinformation contents from the contents server group 500 by way of thenetwork NW100 (step S802). Also, wireless channel have a high-ratetransmission capability.

[0074] The NW communicating section 208 of the communication terminal200 detects a deterioration in a communication environment when thecommunication quality exceeds a predetermined threshold (step S804).When detecting the environmental deterioration, the control section 202refers to the setup information stored in the storage means within thecommunication terminal 200 for responding to the deterioration. Then,according to thus referred setup information, the control section 202prepares for allocating various resources so as to change the visualinformation transmission rate to low-rate visual information. Further,by way of the NW communicating section 208, the control section 202transmits a transmission rate lowering request to the control section110 managing the network NW100 (step S806). Here, the communicationterminal 200 sends an encoding rate lowering instruction to theinformation terminal 300 (step S808).

[0075] The control section 110 of the NW control section 102 notifiesthe contents managing section 116 and information conversion managingsection 118 to change the visual information to low-rate visualinformation, and instructs the corresponding information convertingapparatus 400 and contents server group 500 to do so by way of theservice server interface section 106 (step S810). As a consequence, thehigh-rate visual information provided by the contents server group 500is fed into the information converting apparatus 400, whereby thehigh-rate visual information is converted into low-rate visualinformation in terms of encoding in the image converting apparatus 400(step S812).

[0076] The control section 110 of the NW control section 102 notifiesthe resource managing section 112 to change a resource within thenetwork NW100 to a resource corresponding to a low-rate image signal,whereby the resource managing section 112 allocates resources within thenetwork NW100 (step S814).

[0077] For changing a wireless resource to a resource corresponding tothe low-rate image signal, the control section 110 of the NW controlsection 102 notifies the resource managing section 112 to lower thewireless channel transmission rate, whereby thus notified resourcemanaging section 112 sets and allocates wireless resources (step S816 tostep S818).

[0078] After resources are completely allocated, a transmission ratelowering completion report is transmitted from the communicationterminal 200 to the information terminal 300 and the network 100 (stepS820). In the information terminal 300, on the other hand, switching ofresources is executed, whereby contents are received a low-rate visualinformation (step S822).

[0079] Due to the foregoing operation, not only various old resourcesare released in the network NW100, information converting apparatus 400,and contents server 500 (step S824), but also the old network resourcesin wireless channel and in lines within the network NW100 (lines withinthe NW) are released (step S826).

[0080] Though the above-mentioned embodiment exemplifies a case wherethe rate of image codec is lowered, it is also applicable to mediaconversions to data having a small amount of information such as textinformation, for example. Also, though the above-mentioned embodimentexemplifies a case where the communication terminal 200 and informationterminal 300 are realized as housings independent from each other, i.e.,as the separate type information communication terminal 250 a (see FIG.1), the information communication terminal is not restricted to such aform, whereas one housing in which the communication terminal andinformation terminal are appropriately assembled together, i.e., theintegrated information communication terminal 250 b (see FIG. 1), may beemployed as well.

[0081] (3) Case where a change in the position of a terminal isdetected, and media and transmission means for contents are converted.

[0082]FIG. 9 is a chart showing an example of communication sequence inthe case where a change in the position of a terminal is detected, andmedia and transmission means for contents are converted. Here, FIG. 9conceptually shows only the part relating to the present invention inthe communication sequence.

[0083] First, the information communication terminal 250 b (comprisingthe structure shown in FIGS. 3 and 4) receives contents of visualinformation from the contents server group 500 by way of the networkNW100 (step S602). Here, the network NW100 is a network suitable fortransmitting/receiving visual information, e.g., a packet switching typenetwork or the like.

[0084] The environment detecting section 310 of the informationcommunication terminal 250 b detects an environmental change when thechange in terminal position exceeds a predetermined threshold (stepS604). The detection of change may also be effected, for example, when achange the cell which terminal is located is detected by a celldetermination, the terminal measures its own position according to GPS,a movement is detected by an acceleration sensor installed in theterminal, and so forth. When notified of the environmental change, thecontrol section 302 refers to the setup information stored in thestorage section 316 for responding to the change. Then, according tothus referred setup information, the control section 302 prepares forallocating various resources so as to change contents from visualinformation to audio information.

[0085] When resources are completely allocated, an audio informationrequest signal is transmitted from the information communicationterminal 250 b to the control section 110 of the network NW100 by way ofthe communication interface 312 (step S606).

[0086] Upon receiving the audio information request signal, the controlsection 110 of the NW control section 110 notifies the resource managingsection 112 to change a resource to a resource corresponding to an audiosignal (step S608). Further, the control section 110 of the new controlsection 102 notifies the contents managing section 116 and informationconversion managing section 118 to change information into audioinformation, and instructs the corresponding information convertingapparatus 400 and contents server group 500 to do so by way of theservice server interface section 106 (step S610). As a consequence, thevisual information provided by the contents server group 500 is fed intothe information converting apparatus 400.

[0087] In the information converting apparatus 400, the visualinformation provided by the contents server group 500 is converted intoaudio information (S612). Also, the information converting apparatus 400transmits both audio and visual contents to the network NW100 (stepS614). This aims at preventing information from losing at the time whenswitching network resources.

[0088] When it is verified in the contents managing section 116 of theNW control section 102 that both audio and visual information items aretransmitted, the NW control section 110 of the NW control section 102changes various resources corresponding to the communication terminal200 with respect to the resource managing section 112 and line switchingsection 114. Namely, the line switching section 114 instructs thewireless interface section 104 and gateway section 108 to changeresources (step S616).

[0089] Here, by way of the wireless interface section 104, the NWcontrol section 102 specifies a channel allocated to the informationcommunication terminal 250 and the like (step S612). Also, theinformation communication terminal 250 b carries out a switchingoperation for a communication channel or the like (step S620), andreceives audio information contents by way of thus switched channel(step S622).

[0090] Upon receiving the switching completion report from theinformation communication channel 250 b, the network NW100 carries outprocessing for completing channel switching (step S626), release oldresources of the network NW100, and instructs the information convertingapparatus 400 to transmit audio information alone. Thereafter, theinformation communication terminal 250 b receives only audio informationby way of the information converting apparatus 400 (step S628).

[0091] Here, if the information communication terminal 250 b moves outof the service area of the network NW100 (hereinafter referred to asnetwork NW1) or fails to connect with the current network NW100 due to adeterioration in the status of propagation and the like, communicationscan be continued by switching to another network (hereinafter referredto as network NW2). In this case, an audio information request signaland an NW switching request signal to the network NW2 are sent out. Thenetwork NW1 having received the request for switching to the network NW2requests the NW2 to set a resource necessary for communications, andinstructs the information converting apparatus 400 to execute theabove-mentioned step S614 for the network NW2 as well. The network NW2sets a resource in response to the setting request, and transmits to thenetwork NW 1 notifications of the completion of resource setting and thedestination to which the wireless communication channel is switched. Thenetwork NW1 having received the notifications executes theabove-mentioned step S618 without carrying out the above-mentioned stepS616. Subsequently, the information communication terminal 250 executesthe above-mentioned step S620, and carries out communications in theabove-mentioned step S622 by way of the network NW2. Also, in theabove-mentioned step S624, the information communication terminal 250 btransmits a notification of the completion of switching to the networkNW2, whereby the network NW2 executes the above-mentioned step S626. Thenetwork NW2 notifies the network NW1 that processing for completing theswitching is executed, whereby thus notified network NW1 releasesresources.

[0092] Though the above-mentioned switching process from the network NW1to another network NW2 is a network-driven switching process in whichthe network NW1 sends an NW switching request signal to the network NW2,it may also be a terminal-driven switching process in which theinformation communication terminal 250 b itself directly transmits theNW switching request signal to the network NW2, so as to carry outswitching.

[0093] Though the above-mentioned embodiment explains a case where theinformation communication terminal 250 b is utilized, the separate typeinformation communication terminal 250 a (communication terminal200+information terminal 300) may also be utilized.

[0094] (4) Application to a video conference system

[0095] A case where the mobile communication system according to thepresent invention is applied to a video conference system will now beexplained in detail with reference to FIG. 10.

[0096]FIG. 10 is a view showing an example of image realizing a videoconference employing the mobile communication system according to thepresent invention. Here, FIG. 10 conceptually shows only the part ofvideo conference system relating to the present invention. Also, thefollowing explanation exemplifies a case where a change in terminalcapability or in transmission capability of a wireless area is detected,and an encoding conversion is carried out.

[0097] First, it is assumed that a video conference is held by use of alarge-size TV set with a party in another office connected with a VPN byway of a wireless LAN (network NW1). Here, if one of parties of thevideo conference goes outdoor with a mobile phone, the network NW1 isnotified of the change in terminal, whereby the communication network isautomatically changed from the wireless LAN (network NW1) to a mobilecommunication network (another network NW2), whereas contents areconverted from high-definition visual information for the large-size TVset to a high-compression visual information for a mobile terminal.

[0098] When a participant rides on a bus with a mobile phone, anenvironmental change is detected by local wireless means such asBluetooth installed in the bus, whereby contents are automaticallyconverted from audio information to text information, and then areprovided.

[0099] As in the foregoing, employing the mobile communication systemaccording to the present invention enables “network seamless” forroaming between different kinds of networks, “contents seamless” forconverting different kinds of encoding or media therebetween, and“device seamless” for making it possible to utilize optimum I/O devicesin conformity to surrounding environments. Here, one skilled in the artcan readily see that the mobile communication system according to thepresent invention can be carried out in bidirectional communicationssuch as videophone systems, for example.

Other Embodiments

[0100] Though the foregoing explanation exemplifies a case whereembodiments of the mobile communication system according to the presentinvention and the resource switching method thereof are realizedindependently, the present invention should not be restricted to theabove-mentioned embodiments. For example, one skilled in the art canreadily see that the above-mentioned embodiments can be combinedtogether. Also, while the above-mentioned embodiments exemplify a casewhere the NW control section 102, wireless interface section 104,service server interface section 106, gateway section 108, informationconverting apparatus 400, and contents server group 500 are shown asindependent network resources, one skilled in the art can readily seethat the above-mentioned embodiments can be carried out in apparatus inwhich any parts of these constituents are combined together asappropriate.

[0101] Though the above-mentioned embodiment exemplifies the service,system, scheme, and the like of NTT DoCoMo, Inc. (company name), it isalso applicable to services, systems, schemes, and the like of othercompanies having similar functions.

[0102] Further, though the above-mentioned embodiment exemplifies theprocedure of allocating new resources and releasing old resources, oneskilled in the art can readily see that, without changing a physicalchannel in a wireless area or network NW, its transmission rate or theencoding rate of contents to be communicated can be changed alone asrequired.

[0103] From the foregoing explanations, it will be obvious that thepresent invention may be varied in many ways. Such variations are not tobe regarded as a departure from the spirit and scope of the invention,and all such modifications as would be obvious to one skilled in the artare intended to be included within the scope of the following claims.

Industrial Applicability

[0104] In the present invention, as mentioned above, if an environmentalchange concerning any object is detected in any of apparatus of a mobilecommunication system, e.g., a mobile terminal, an information processingapparatus connected to the terminal, a node within a communicationnetwork, a node connected to the network, and the like, at least oneapparatus relating to the change is notified of the result of detection,whereby various resources are set up and switched in thus notifiedapparatus so as to respond to a new environment. This automaticallyeliminates seams (restrictions) resulting from changes in communicationenvironment and terminal capabilities and the like, whereby a seamlessnetwork is constructed with respect to various environmental changes.Namely, the present invention enables “network seamless” for roamingbetween different kinds of networks, “contents seamless” for convertingdifferent kinds of encoding or media therebetween, and “device seamless”for making it possible to utilize optimum I/O devices in conformity tosurrounding environments.

[0105] Also, though the conventional mobile communication system havefailed to automatically switch communication environments and the likein response to user environments, the present invention canautomatically execute switching in response to environments. Differentqualities in the same media can also be switched.

[0106] Further, the present invention enables switching betweendifferent media, and also makes it possible to modify apparatus andfunctions in a form conforming to conditions under which contents arerequired.

1. A mobile communication system comprising: detecting means fordetecting at least one of a change in an environment in which an objectto be inspected exists and a change in a capability of said object to beinspected; reporting means for notifying one or more apparatusesrelating to said change detected by said detecting means of at least aresult of said detection; setting means for newly setting at least oneof a network resource and an information format in conformity to saidchange detected by said detecting means; and switching means forswitching said network resource and information format into a contentset by said setting means.
 2. A mobile communication system according toclaim 1, wherein said object to be inspected includes at least one of acommunication terminal, transmission means for a radio area, andtransmission means within a network.
 3. A mobile communication systemaccording to claim 1, wherein said network resource includes at leastone of a wireless communication channel, a transmitter/receiver, a linewithin a network, a communication node apparatus, a communicationterminal, an information switching apparatus, and an informationconverting apparatus.
 4. A mobile communication system according toclaim 1, wherein said switching means includes information convertingapparatus which carries out, as said switching of information format, atleast one of changing of media for information transferred over anetwork and changing of a transmission quality between the same media.5. A mobile communication system comprising: a network, having aresource, for transferring information to be transmitted/received by amobile terminal; a network control section for controlling said network;and an information converting apparatus, as information format switchingmeans with respect to information transferred over said network, forcarrying out at least one of changing of media for informationtransferred over said network and changing of a transmission qualitybetween the same media in accordance with an instruction from saidnetwork control section.
 6. A mobile communication system according toclaim 5, wherein said information converting apparatus comprises: anetwork interface section for transmitting/receiving information to/froma resource constituting said network; an information converting sectionfor converting a format of information captured through said networkinterface section into another format, and sending out thus convertedinformation to said resource constituting said network by way of saidnetwork interface section; and a control section for controlling saidinformation converting section in accordance with an instruction fromsaid network control section captured through said network interfacesection.
 7. A resource switching method for a mobile communicationsystem, said method comprising: a detecting step of detecting at leastone of a change in an environment in which an object to be inspectedexists and a change in a capability of said object to be inspected; areporting step of notifying one or more apparatuses relating to saidchange detected by said detecting step of at least a result of saiddetection; and a setting step of newly setting at least one of a networkresource and an information format in conformity to said change detectedby said detecting step; and a switching step of switching said networkresource and said information format into a content set by said settingstep.
 8. A resource switching method for a mobile communication systemaccording to claim 7, wherein said object to be inspected includes atleast one of a communication terminal, transmission means for a radioarea, and transmission means within a network.
 9. A resource switchingmethod for a mobile communication system according to claim 7, whereinsaid network resource includes at least one of a wireless communicationchannel, a transmitter/receiver, a line within a network, acommunication node apparatus, a communication terminal, an informationswitching apparatus, and an information converting apparatus.
 10. Aresource switching method for a mobile communication system according toclaim 7, wherein said switching step includes a step of carrying out, asswitching of said information format, at least one of changing of mediafor information transferred over a network and changing of atransmission quality in the same media.
 11. A network control methodcomprising the steps of: receiving a detection report of at least one ofa change in an environment in which an object to be inspected exists anda change in a capability of said object to be inspected from said objectto be inspected; determining at least one of a network resource and aninformation format suitable for said change specified by said detectionreport received from said object to be inspected; and controlling saidobject to be inspected concerning at least one of said determinednetwork resource and information format so that said object conforms tosaid detected change.
 12. A network control method according to claim11, wherein said object to be inspected includes at least one of acommunication terminal, transmission means for a radio area, andtransmission means within a network.
 13. A network control methodaccording to claim 11, wherein said network resource includes at leastone of a wireless communication channel, a transmitter/receiver, a linewithin a network, a communication node apparatus, a communicationterminal, an information switching apparatus, and an informationconverting apparatus.
 14. A network control apparatus comprising:receiving means for receiving a detection report of at least one of achange in an environment in which an object to be inspected exists and achange in a capability of said object to be inspected from said objectto be inspected; determining means for determining at least one of anetwork resource and an information format suitable for said changespecified by said detection report received from said object to beinspected; and control means for controlling said object to be inspectedconcerning at least one of said determined network resource andinformation format so that said object conforms to said detected change.15. A network control apparatus according to claim 14, wherein saidobject to be inspected includes at least one of a communicationterminal, transmission means for a radio area, and transmission meanswithin a network.
 16. A network control apparatus according to claim 14,wherein said network resource includes at least one of a wirelesscommunication channel, a transmitter/receiver, a line within a network,a communication node apparatus, a communication terminal, an informationswitching apparatus, and an information converting apparatus.